Liquid f



April 1941- R. M. SHERMAN 2,240,380

LIQUID FUEL BURNER Filed Nov. 25, 19.39 2 Sheets-Sheet 1 Inveni aw: RaZZs ionliikfl'man;

R. M. SHERMAN LIQUID FUEL BURNER April 29, 1941.

Filed Nov. 25, 1939 2 Sheets-Sheet 2 I nveni/ oa' RaZZs F70 72/1! Sherman 7 difi 'yq Patented Apr. 29, 1941 UNETED STATES PATENT OFFICE 2,240,380 LIQUID FUEL BURNER Rallston M. Sherman, Glastonbury, Conn. Application November 25, 1939, Serial No. 306,088 r Claims. (Cl.158-'-90) This invention relates to burners employing liquid fuel (for descriptive purposes herein referred to as oil) and to methods of igniting such burners, and more particularly to those in which a wick or the like is employed for starting the burner.

The invention is herein illustrated in connection with a burner of the combustion tube type in which an oil-saturated, fire-resisting, asbestos wick is lighted andused preliminarily to heat the burner.

The most effective method of electrically starting a burner of this type is through the use of an ignition spark. Ignition devices of this type as heretofore proposed have certain disadvantages which render them unfitted for practical use where certainty of prompt action without frequent attention is required, as, for example, where a burner of this type is employed for house heating and is to be started at frequent unpre-= dictable intervals through automatic, thermostatic control.

In most of such prior devices reliance is placed on the direct igniting action of a jump spark on the asbestos wick itself. This results in an uncertain and haphazard action due to the fact that the asbestos wick consists of a woven structure with a certain measure of limpness. The position of the wick relatively to the sparking electrode and its igniting spark, even if dflnitely fixed at the outset, is subject to variation and cannot be definitely predetermined under conditions of subsequent use. This not only renders the action on the wick of the igniting spark uncertain but causes uncertainty in the production of any spark at all, since it leads to variation in the length of the spark gap, which latter should be fixed and definite within close limits reliably to produce a spark. Asbestos wicks of the type used in combustion tube burners consist of woven asbestos, reinforced interiorly by copper wires threaded through the wick and forming a loosely woven mat. These wires become grounded on the base, and where the spark cts against the starting wick the position of these wires determines the length of the gap and the certainty of creating any spark at all. Owing to the uncertain position of the wick and of the reinforcing wires therein with relation to the electrode, reliance on an ignition spark directed against the wick renders the lighting of the wick and the generation of the spark itself more or less fortuitous. Furthermore, the repeated action of the spark on the reinforcing wires tends to disintegrate them by burning with theresultant disintegration of the Wick through lack of s pp Many of such prior igniting devices are complicated or impracticable in their attachment to the burner, rendering the latter practically unsuitable for use due to the fact that such attachment requires the cutting of openings through the oil retaining walls of the burner (a practice contrary to the established underwriters rules), with attendant danger of oil leakage.

I In many of such prior ignition devices, furthermore, reliance is placed on the location of the sparking electrodeiin the combustion chamber where it is subject to the intense destructive heat there generated, with a resultant short life or deterioration of the electrode as well as that of its insulating attachment, and is also subject to the carbonizing actionof the wick flame, requiring frequent cleaning or replacement to render the electrode effective for producing a spark.

One object of the present invention, among others, is the provision of means for electrically lighting the wick through the agency of a jump spark by a simple procedure, under safe and practical conditions which insure a quick starting of the burner with dependability in operation at all times, without the necessity for frequent or continued attention in respect to the condition of theelectrode and. which make it applicable to automatic startingwhere the burner is used with thermostatic control for house heating or other purposes.

In the illustrated embodiment of the invention, these objects are achieved by locating the sparking electrode in a space below and away from the combustion chamber and preferably at one side of the wick channel, where the electrode is held in a definite, fixed, spaced relation to a second electrode grounded on the base and also below and away from the combustion chamber, the spark generated in the intervening gap being relied on to ignite the oil absorbed by a pilot wick member, the walls of which are also held in definitely fixed, spaced relation to and closely adjacent the spark gap, the pilot wick serving to communicate its flame to the starting wick or wicks,

This and other objects of the invention will be best understood by reference to the following description, taken in connection with the accompanying illustration showing one specific embodiment thereof, while its scope will be more particularly pointed out in the appended claims.

In the drawings- .Fig. 1 is a plan View of a combustion tube burner embodying one form of the invention, the shells or combustion tubes above the burner base being removed and the cover plate for the base being partly broken away;

Fig. 2 is a partial section on the arcuate line 2--2 in Fig. 1, showing the relation of the igniting element to the starting wick and the burner base;

Fig. 3 is a partial section in elevation on the line 33 in Fig. 1,- taken through the igniting devices, and having the combustion tubes partly broken away;

Fig. 4 is a sectional elevation on the line 4-4 in Fig. 1; and I Fig. 5 is a diagram of the wiring and control connections for the starting of the burner.

Referring to the drawings and to the specific embodiment of the invention shown, there is illustrated a burner unit of relatively high capacity which may be used alone or with other like units and of a type suitable for house heating. This is provided with a base i in the form of a metallic casting having a relatively wide outer annular portion 3 (Fig, 4) and two successive inner annular portions 5 and 1 separate from each other but connected each to the'ad jacent portion by a series of four sets of equally spaced webs (Fig. 1) comprising the three webs 9 and a wider web 9a. These provide an'annular air admission opening ll between the two inner annular portions 5 and 7, interrupted only by the webs 9 and 9a, and a similar air admission opening l3 between the annular portions 3 and 5.

The inner annular portion 7 is provided with a central air admission opening ll, surrounded by an upstanding ring-like flange I9, the outer edge of the inner portion having a similar flange 2| spaced from but concentric with the flange the Wider channel 35.

|9. Ihese flanges, together with the connecting spaced from the flange 3| so as .to form between: 'them' a relatively wide annular fuel compartment or channel 35.

The several channels 23, 29 and are connected to each other by means of ducts 31 and 31a formed in the webs 9 and 9a, respectively,"

so that a free circulation of liquid and vaporized oil may take place in and throughout all fuel channels. Oil is supplied to the'outer channel through two diametrically opposite oil inlets 39 (Figs. 1 and 2) by usual pipe connections,=

not shown. Annular grooves 4| are formed in the bottom of the wide channel 35, which grooves extend with a slightly increasing depth from or them a simiadjacent each oil inlet 39 to a point opposite the duct 31a, where they terminate in a common sump-like depression 43.

The outside of the wide channel 35 is' partly covered and closed by the annular cover plate 45, the outer edge .of which fits over and on the upper edge of the fiange'with a preferably which the oilvapoz may pass directlyiintoathe' space between the flange and the edge of the cover plate.

The inner edge of the cover plate has a raised lip provided with a shouldered edge on which is removably supported a perforated sheet metal cylinder 41 constituting the outer one of a pair of combustion tubes. A similar but smaller concentric cylinder 49 is seated on the top of the shouldered flange 3| so that there is provided between the two cylinders an elongated combustion chamber 5| aligned with and constituting an extension of the inner uncovered portion of Two concentric spaced perforated sheet metal cylinders 53 and 55 are likewise removably seated on shoulders, respectively, of the flanges 21 and 25, and similar cylinders 51 and 59, respectively, on the flanges 2| and I9, providing chambers 3| and 63 having a relation to the fuel channels 29 and 23, respectively, similar to that of the combustion chamber 5| to the inner portion of the channel 35.

Removable annular top plates 65 and 5'! (Fig, 3) are provided with edges resting on the tops of the sheet metal, one on the cylinders 49 and 53 and another on the cylinders 55 and 51, to close the tops of the annular air spaces therebetween, and a disk-shaped closure 69 with its edges resting on the upper edge of the cylinder 59. is similarly provided to close the top of the central air chamber, leaving however annular openings in the tops of the combustion chambers 5|, 6| and 63.

A burner of this type is commonly started by igniting an oil-saturated wick comprising a fabricated strip of asbestos, reinforced by copper wires, the strip being so cut as to rest on edge .in the fuel channel, with its upper edge entered into the bottom of the overhead registering combustion chamber, as indicated in Figs. 3 and 4. In the illustrative device, three such wicks H are shown, one in each of the three fuel chan- I nels. These starting wicks preferably have those :portions which coincide with the connecting ports 31 cut away to leave such ports unob- *structed to the passage of liquid or vaporized oil, and are cut out (as indicated in Fig. 2 in the case of the Wick in the outer channel) so as "to partly bridge oroverhang the underlying igniting wick member (hereinafter described), while-leaving anintermediate space for the free action of the flame arising from such igniting or pilot wick.

When the burner is to be started, oil is ad- ;mitted through the'inlet ports 39, and, entering the wide channel 35, flows over the latter and through the ducts 3'! into and over the inner channels, and, reaching a slight depth in said channels, penetrates the bottom edges of the asbestos wicks and saturates the bodies thereof. "The wicks being lighted, the burner begins to heat, and when the required vaporizing temper- -ature is reached the liquid oil becomes vapor- :ized on entering the Wide vaporizing channel 35 beneath the cover plate 45, the. covered portion thereof constituting a vaporizing space. Combustion is then carried on at an increasing degree independently of. the wicks, and finally e'broug'ht to a completed state through the oil ivapor'passing from the vaporizing chamber into "the several combustion chambers through the ducts 31, the wick ceasing to have any substantial function when the burner operates under 'fullfire -:iTh"described'forrh 'of burner serves to illusmore abutting sections.

trate the application of one form of the invention, but the latter is not limited to the specific burner construction shown and such construction may be widely departed from in the utilization of the invention.

For electric ignition the burner is provided (Fig. 3) with a sparking electrode 12 carried in an insulating sleeve or plug 13 which is entered into the vaporizing space, being screwed into and through a boss on the top of the cover plate 45 so that the electrode projects downwardly and its tip occupies a fixed, predetermined position inthe vaporizing channel at a definite height above the bottom thereof.

To create an igniting spark, the electrode constitutes one terminal of an electric circuit, the opposite terminal being grounded on the base I of the burner. To assure the maintenance of a spark gap of definite and varying length and the certain production of an effective spark there is preferably employed a second conductive electrode 15 having grounded contact with the base, and herein in an upstanding relation in a fixed and predetermined position immediately beneath the electrode 12. To assure of such relationship the angular position of the cover plate on the base may be definitely predetermined by an interfitting formation between the outer flange 33 of the base and the contacting edge of the cover plate. The top of the electrode I preferably extends to a height somewhat above the controlled level reached by the oil in any operation of starting the burner.

v The spark generated in the intervening gap between the two electrodes, instead of acting directly on the asbestos wick to light the same, acts first to fire a pilot or igniting wick element which is held in fixed relation to the sparking gap and in igniting relation to the three starting wicks 'H of the burner and which communicates its flame to the said wicks. Such igniting wick member herein comprises an elongated block 11 of fire resisting material such as molded or baked fire clay of high porosity and oil absorbent capacity. The igniting member fits into a slightly depressed channel formed in the bottom of the wide duct 31a and extends lengthwise such duct with its sides seated between the sides and its ends between the ends of such channel, thereby giving it a definitely fixed position. The block 11 may be formed in a single piece, or, to facilitate application to the burner, may be made in two or The block is herein provided on its top side with a longitudinal channel I9 (Fig. 2) and'the electrode 15 is positioned in igniting relation to the pilot wick member, herein by being embedded near the end thereof in its walls, so that the bottom of the electrode contacts with the bottom of the base andits uncovered top leaves an open spark gap closely adjacent to, and herein surrounded :by, the porous oil saturated walls of the pilot wick member. The block extends lengthwise the duct 37a beneath each of the three wicks, leaving however an open space in the top of the duct for the free action of the flame. V

The electrode 15 may be of any conductive metal, such as copper or other material, and may be molded into the block 11 when the latter is formed, the electric spark when generated acting on the oil which will spread over the walls of the porous block, which walls are held in close relation to the spark gap.

The electrode 15, however, may be and preferably is formed of conductive material which is Ell itself more or less oil absorbent. Such oil absorbent electrode may be provided by forming a plug of the material known under the tradename of Carbofrax, consisting of silicon carbide crystals mixed with a small amount (such as 15%) of aluminum oxide, the mixture being rendered plastic by the addition of water glass and such plug being molded into the igniting wick when the latter is formed. In this case the oil conducted to the surface of the electrode, as well as the oil on the surface of the pilot wick member, becomes ignited by the spark and the flame from the pilot wick member is communicated to the star-ting wicks as previously described. The entire igniting wick might be formed of conductive Carbofrax or other absorbent conductive material, but preferably, to provide a spark gap of definitely fixed length and position as well as to avail of the greater porosity {obtainable throughout the entire body of the pilot wick member, the electrode 15 only is conductive and the remainder of the igniting wick is porous and non-conductive, being formed preferably of earthy or other such material as will result in a substantially rigid body or mass.

In the starting operation of the burner, when oil is admitted to the outer vaporizing channel, however slight is its depth in the channel, the groove ti in the bottom thereof assures its access to the pilot wick and the prompt and complete saturation of the latter by the oil, as well as the saturation of the electrode 15, if thelatter is of oil absorbent material, both the electrode and the pilot wick setting directly in the sump 43 (Fig. 2).

Normally, in the starting of the burner, the

controlled level of the oil will limit this depth to a level below that of the top of the electrode 15. When the spark jumps across its gap, the oil gathered in and adjacent the spark gap is instantly vaporized and ignited land the flame promptly spreads over the entire length of the starting wick member, flaring up into the space above the same and aroundand against the edges of the overlying asbestos wicks, with a quick and certain firing of the latter.

A peculiar feature of the described igniting device is the fact that promptly after the ignition of the igniting wick and the firing of the asbestos wicks, the spark automatically ceases, this being doubtless due to the profusion of oil vapor in the gap and the resultant exclusion from and absence of air in .the vaporizing groove in and about the gap. Accordingly, no interruption of the electric sparking circuit is required to stop further sparking, a feature which simplifies the automatic, thermostatic control of such a burner.

It will be observed that the sparking takes place between electrodes which are both located out of the combustion chamber, away from the efi'ects of the flame therein and from the carbonizing action of the wick, the same being herein located in a vapor compartment below the combustion chamber, at the side of and communicating with the wick containing fuel channel and specifically in a chamber below and beyond the peripheral limits of the outer combustion chamber.

Due to its attachment to the outside vaporizing plate, the electrode i2 is entered into the vaporizing chamber from above and no cutting through or mutilation of the oil retaining walls of the burner is required for its installation.

Both electrodes are readily accessible for examination, or for cleaning, if and when necessary,

although their relation to the wick andcom- 'bustion chamber and their positions in the vatubes forming combustion chambers porizing space render such cleaning seldom necessary. Both the electrode 72 and its companion electrode 75 are held in a fixed position,

giving an unvarying spark gap which: is independent of the fortuitous position which the asbestos starting wick or wicks may occupy at any time and the rigidity of the igniting wick member H, and the broad area over which this flaring flame acts renders the prompt firing of the asbestos wick certain.

The described burner when used for house heating purposes may be started and stopped by automatic control means, as indicated in Fig. ..5. [Ihe burner I is there connected to be supplied with oil through the feed pipe 80 from a source not shown but through which a limited oil level is maintained in the burner base. The

, oil supply is normally cut off by a valve 8! which nal of the secondary of such transformer being connected to the electrode 12 and the other terminal to the burner base.

While I have herein shown and described for purposes of illustration one specific embodiment of the invention, it is to be understood that the details illustrated and the form or relative arrangement of-parts may be widely varied, all

without departing from the spirit of the invention.

I claim:

1. A liquid fuel burner having a base with spaced annular upstanding walls defining between them an outer annular fuel chamber and a laterally spaced inner annular fuel chamber, 4

pairs of spaced annular concentric combustion in upstanding relation to and opening each from one of said fuel chambers, the outer fuel chamber being of greater width than the inner one, a removablecover plate overlying and covering the outer portion of the wider fuel chamber but leaving an uncovered inner channel portion opening into and registering with the outer overhead combustion chamber and providing a,

covered annular space at the outside of and communicating with said inner channel portion, a fuel supply duct connecting the inner and outerfuel chambers, means for supplying Liquid fuel to the outer one of said fuel chambers, starting wicks one in each of said fuel chambers, an "electric spark electrode in the base entered through, supported by and removable with the cover plate and connected to create an igniting spark, and means for igniting the starting wicks through the effect of a spark created by said electrode.

2. A liquid fuel burner having combustion tubes forming a combustion chamber, a base supporting said tubes and having an annular fuel chamber, an annular covering member for the chamber extending inwardly from the outer wall thereof to partly cover the same, with its extending walls' spaced from the inner wall of the chamber to leave an uncovered channel portion thereof opening into and registering with the overhead combustion chamber" and providing a covered annular space below and outside the peripheral limits of said combustion chamber but communicating with said channel portion, a liquid fuel absorbent starting wick positioned in said channel portion to project its flame into said combustion chamber, a sparking electrode entered through the walls of said covered space, and means for igniting the wick through the effect of a spark created by said electrode.

3.;A liquid fuel burner having combustion tubes forming a combustion chamber, a base supporting said tubes, and having an annular fuel chamber, an annular covering member for the chamber extending, from one wall thereof to partly cover the same, its extending walls being spaced from the opposite wall of the chamber to leave an uncovered annular channel portion thereof opening into and registering with the overhead combustion chamber and providing a covered annular space below and at one side of the peripheral limits of the combustion chamber but communicating with said uncovered channel portion, means for supplying liquid fuel to said chamber, a liquid fuel absorbent starting wick positioned in said channel portion to project its flame into said combustion chamber, a sparking electrode entered through the walls of said 'covered'space, and means for igniting the wick 0 through the effect of a spark created by said electrode.

4. A liquid fuel burner having spaced annular upstanding walls defining between them an outer annular fuel channel and a laterally spaced inner annular fuel channel, pairs of spaced concentric combustion tubes forming combustion chambers in upstanding'relation to and opening each from one of said fuel channels, a duct connecting said fuel channels, means for supplying liquid fuel to said base, astarting wick in each of said fuel channels, means for supplying liquid fuel to said channels, said base'having a formation presenting a covered chamber at a side of and communieating with a fuel channel, an insulating memberentered through the walls of said chamber and presenting a spark electrode below the level of said combustion chamber and the upper edges of said starting Wicks, a second electrode grounded on the base and spaced below said first electrode to provide a spark gap, and a pilot wick member in said base in igniting relation to the spark created between said electrodes, said pilot wick member extending into the connecting duct between said channels and in such relation to said starting wicks as to light the latter from its flame.

5. A liquid fuel burner having combustion tubes forming a combustion chamber, a base supporting said tubes and having a fuel channel beneath ing a formation presenting a covered chamber at a side of said fuel channel and communicating with the latter, an insulating member entered through the walls of said chamber and presenting an electric spark electrode in said covered chamber below the upper edge of the starting wick,

7 -a secondelectrode grounded on the base and gap, and a pilot wick member in the base comspaced from said first electrode to provide a spark municateits flame to the starting wick, said second electrode'being held in said pilotwick member with the walls of the latter in close igniting relation to the'spark created in said gap.

6. 'A liquid fuel burner having combustion tubes forming a combustion chamber, a base supporting said tubes and having a fuel channel beneath and opening into said combustion chamber, a starting wick in said fuel channel, means for supplying liquid fuel to said channel, an electric spark electrode associated with said base, a substantially rigid, liquid fuel absorbent body constituting a pilot wick member positioned insaid base to communicate its flame to the starting wick, said body having an opening therein, and a second electrode in said opening grounded on the base and spaced fromv the first electrode to leave an intermediate spark gap surrounded by the walls of said pilot wick member.

'7. A liquid fuel burner having combustion tubes forming a combustion chamber, a base supporting said tubes and having a fuel channel beneath and opening into said combustion chamber, a starting wick in said fuel channel, means for supplying liquid fuel to said channeLsaid base having a formation presenting a covered chamber at a side of said fuel channel and communicating with the latter, an electric spark electrode in said chamber, a second electrode also in said chamber grounded on the base underneath and spaced from said first electrode to provide an intermediate spark gap, and a pilot wick member in ignit-' ing relation to said gap and in position to communicate its flame to the starting wick.

8. A liquid fuel burner having combustion tubes forming a combustion chamber, a base supporting said tubes and having a fuel channel beneath and opening into said combustion chamber, a starting wick in said fuel channel, means for supplying liquid fuel to said channel, said base having a formation presenting a covered chamber at a side of said fuel channel and communicating with the latter, an electric spark electrode in said covered chamber, a second electrode also in said chamber grounded on the base and spaced from said first electrode to provide an intermediate spark gap, and a pilot wick member in igniting relation to said gap and in position to communicate its flame to the starting wick.

9. A liquid fuel burner having combustion tubes forming a combustion chamber, a base supporting said tubes and having a fuel channel beneath and opening into said combustion chamber, a starting wick in said fuel channel, means for supplying liquid fuel to said channel, said base having a formation presenting a covered chamber at a side of said fuel channel and communicating with the latter, an electric spark electrode entered into i the base through the walls of said covered chamber, a liquid fuel absorbent, fire-resisting, electrically-conductive body constituting a second electrode grounded on the base and spaced from said first electrode to provide an intermediate spark gap, and a pilot wick member in igniting relation to said gap and in position to communicate its flame to the starting wick,

10. A liquid fuel burner having combustion tubes forming a combustion chamber, a base supporting said tubes and having a fuel channel beneath and opening into said combustion chamber, a starting wick in said fuel channel, means for supplying liquid fuel to said channel, an electric spark electrode associated with the base, a liquid fuel absorbent, fire-resisting, electricallyconductive body constituting a second electrode grounded on the base and spaced from said first electrode to provide an intermediate spark gap below the level of the upper edge of said starting wick, and a separate pilot wick member in igniting relation to'said gap and in position to communicate its flame to the starting wick.

11. A liquid fuel burner having combustion tubes forming, a combustion chamber, a base supporting said tubes and having a fuel channel beneath and opening into said combustion chamber, a starting wick in said fuel channel, means for supplying liquid fuel to said channel, said base having a formation presenting a covered chamber at a side of said fuel channel and communicating with the latter, an electric spark electrode entered into said base through the walls of said covered chamber, a second electrode grounded on the base and in spark creating relation to said first electrode, said second electrode being composed of electrically-conductive, fuel-absorbent, fire-resisting material and adapted to be saturated with the liquid fuel admitted to said channel, and means for igniting the starting wick through the flame creating effect of a spark produced between said electrodes.

12. A liquid fuel burner having combustion tubes forming a combustion chamber, a base supporting said tubes and having a fuel channel beneath and opening into said combustion chamber, a starting wick in said fuel channel, means for supplying liquid fuel to said channel, an electric spark electrode associated with the base, a liquid fuel absorbent, fire-resisting, electricallyconductive body constituting a second electrode grounded on the base and spaced from said first electrode to provide an intermediate spark gap below the level of the upper edge of said starting wick, and a pilot wick member composed of a body of porous, liquid fuel absorbent, non-conductive material in igniting relation to said gap and in position to communicate its flame to the starting wick.

13. A liquid fuel burner having combustion tubes forming a combustion chamber, a base supporting said tubes and having a fuel channel beneath and opening into said combustion chamber, a starting wick in said fuel channel, means for supplying liquid fuel to said channel, said base having a formation presenting a covered chamber at a side of said fuel channel and communicating with the latter, an electric spark electrode entered into the base through the walls of said covered chamber, and a substantially rigid, porous body composed of fire-resisting, liquid fuel absorbent material and constituting a pilot wick member held in a fixed position in said base and extending from said covered chamber in a direction transverse said fuel channel, said pilot wick member being in igniting relation to the spark created by said electrode and in position to communicate its flame to the starting wick.

14. A liquid fuel burner having a base with walls defining a fuel channel, combustion tubes surmounting said base and forming a combustion chamber above said channel, a liquid fuel absorbent starting wick positioned in said channel, means for supplying liquid fuel to said channel to saturate said starting wick, a fuel absorbent pilot wick member in the base in igniting relation to said starting wick, and means for creating an electric spark to light the pilot wick, the bottom of said channel being provided with means for accelerating the conduct of liquid fuel to said pilot wick member to assure prompt saturation thereof on the admission of liquid fuel to the channel.

15. A liquid fuel burner having a base provided substantially rigid body fixed in position in a seat depressed in the base below the level of the fuel inlet, whereby said pilot wick member is subject to saturation by liquid fuel entering said inlet,

- and means for creating an electric spark to light the pilot wick member.

' RALLSTON M. SHERMAN. 

